1. Field of the Invention
The present invention relates to a permanent mooring method and arrangement for embedding a permanent mooring device in a sea bottom. More particularly, the invention relates to a method and arrangement wherein fluid is transmitted under high-pressure through a bottom nozzle of a permanent mooring device so as to create a fluidized area in the sea bottom around the permanent mooring device, thus washing the mooring device into and beneath the sea bottom, followed by a transmission of a cementitious substance through the permanent mooring device into the fluidized area of the sea bottom, thus filling that area in the sea bottom with the cementitious substance. Subsequently, the cementitious substance consolidates around the permanent mooring device. Vibration is utilized, during one or more of the various steps of the procedure, to assist in establishment of the permanent mooring.
2. Description of the Prior Art
In recent years, the necessity for establishment of permanent moorings has increased. For example, the increase in the popularity of the sport of boating has resulted in less space being available to moor boats in marinas, and accordingly, due to the insufficient dockage, it has become the practice to moor boats in small bays, inlets, estuaries, or the like, located adjacent to the dock areas of yacht clubs and marinas.
In addition, the increase in large-scale off-shore activities, such as off-shore oil exploration, has increased the need for permanent moorings of extremely high strength. Such extremely strong permanent moorings are necessary, for example, in the stabilization of off-short oil drilling platforms.
Early attempts to achieve permanent moorings consisted of the positioning, along the sea bottom, of large blocks of concrete with eyelets embedded therein. Such techniques had various disadvantages, and the present inventor has previously presented in U.S. Pat. No. 4,312,289, issued on Jan. 26, 1982, a description of the disadvantages of the earlier prior art techniques, as well as a disclosure of a permanent mooring apparatus having significant advantages over the earlier techniques.
The permanent mooring apparatus disclosed in the aforementioned patent was preferably formed of metal and had foldable flukes. The previously disclosed mooring was intended to be driven into the sea bottom by means of water pressure emitted from a nozzle at the lower end of the device, and by downward force applied to pipe sections, by means of which the permanent mooring had been lowered to the sea bottom. According to the previously disclosed technique, once the permanent mooring was washed into and beneath the sea bottom to a sufficient depth, the water pressure was discontinued, and any attempt to retract the permanent mooring from the sea bottom resulted in unfolding of the flukes which then grasped the sea bottom, thus creating a permanent mooring.
Such a permanent mooring apparatus as was disclosed in the aforementioned patent had some disadvantages. For example, the device did not attain its full holding capacity because of the liquefaction of the sea bottom caused by the constant pulls exerted upon it by the surface vessel, especially if the device was utilized for large-scale applications. Thus, this ineffectiveness resulted from the fact permanent mooring previously disclosed relied, for its strength and resistance, merely on its ability to grasp the surrounding medium making up the sea bottom, and that medium can be very loose and fluid in places.
In addition, the previously disclosed procedure for establishing the permanent mooring was time-consuming due to the fact that only a combination of transmission of high-pressure fluid through the permanent mooring device and downward pressure on the pipe sections connected to the top of the mooring device was employed for the purpose of washing the device into the sea bottom.
Various other patents (in addition to the inventor's previous patent) have disclosed techniques involving the fluidization of the sea bottom to assist in the embedment of an anchor or mooring: U.S. Pat. Nos. 3,408,819; 4,086,866; 4,095,550; and 4,347,802. Other patents have disclosed techniques utilizing vibration for the purpose of embedding an anchor in the sea bottom, for example: U.S. Pat. Nos. 3,118,417; 3,417,724; and 3,850,128. Still other patents have disclosed techniques involving action-reaction phenomena induced for the purpose of embedding the anchor in the sea bottom, for example: U.S. Pat. Nos. 3,371,643; 3,604,519; and 3,750,609, Further patents disclose the use of vibration techniques in applications other than anchor embedment, for example: U.S. Pat. Nos. 2,334,228; 2,672,322; 3,245,223; 3,295,837; and 3,865,501.
Furthermore, the prior art technology has included various attempts to establish permanent moorings both within the sea bottom and within earth formations. For example, the following patents are typical: U.S. Pat. Nos. 721,663; 1,086,053; 1,315,721; 1,373,067; 2,229,912; 3,123,037; 3,130,552; 3,207,115; 3,262,412; 3,332,387; 3,653,355; 4,033,281; and 4,080,923.
Other prior art techniques involve the use of explosive charges to drive a mooring device into the sea bottom, but such techniques are expensive and requiring mooring devices which are complicated and/or not self-contained.
The following patents are of background interest with regard to the presently disclosed invention: U.S. Pat. Nos. 372,940; 454,717; 1,743,431; 1,950,947; 2,159,116; 2,460,352; 2,583,965; 2,703,544; 2,982,244; 3,054,123,3,187,705; 3,212,110; 3,215,454; 3,291,092; 3,311,080; 3,621,805; 3,817,040; 3,910,218; and 4,345,785.